This invention relates generally to the field of collapsible, reusable shipping containers, and more particularly to an improved form thereof, suitable for transporting manufactured subcomponents to a point of assembly where the container serves as a storage bin adjacent an assembly line. While the invention has application in a wide variety of assembly procedures, it has particular utility in the assembly of automotive vehicles and the like.
In the assembly of relatively large components to form a completed product, components are normally individually wrapped or packaged, following which they are placed in a larger container for shipment to a point of assembly. Upon arrival, they are individually removed from the larger container, unwrapped and positioned at a point along the assembly line for subsequent integration. To facilitate such positioning, the components are sometimes positioned in trays which are stacked within the larger container, and the trays are removed from the container in serial fashion.
The problems accompanying such procedure are readily apparent. In some cases, the components must be individually unwrapped leaving wrappers to be discarded. In the case of the above-mentioned stacked trays, the trays must be stored after removal of the components therefrom to occupy valuable space adjacent the assembly line. If the trays are reusable, they also occupy sufficient space within the larger container to prevent the container from being collapsed for return shipment. Where the components are relatively heavy, it is difficult to remove the supporting trays from the container since they must be lifted from the side edges thereof, thus requiring access to the container on all sides thereof for manual engagement.
In the above-identified copending application, there is disclosed an improved shipping container of the class described in which the above-mentioned difficulties have been substantially eliminated. The shipping container comprises a collapsible, reusable, generally rectangular box element which is preferably supported upon an interconnected rigid pallet of known type. One of the vertical side walls of the container defines an opening therein providing access to the interior thereof after removal of an upper lid element and a front door. The upper horizontal edges of a pair of oppositely disposed side walls on either side of the opening are reenforced, and are provided with channel-forming members which support a plurality of elongated supporting bars therebetween for movement laterally toward and away from the opening. The bars, in turn, support along the length thereof, plural strap-like cradles, each including plural segments which jointly support elongated components in vertically stacked relation. The segments are individually opened to allow release of individual parts for removal as required starting from the lowermost part in a given stack. When all of the parts in a single stack have been removed, the corresponding bar is also removed, and the immediately adjacent bar is moved in a direction toward the access opening where the process is repeated until the parts carried by the successive stacks have been removed. With the removal of the last stack, the bars and cradles may be stored upon the bottom wall of the container, following which the container is then collapsed along fold lines above and parallel to the bottom wall to allow return shipment of the container to a point of origin while occupying substantially reduced volume.
The above-described structure, while making a significant contribution to the art, does not provide for certain recently discovered problems. A first is the shifting of backed contents within the container, which, in extreme cases, can create a pendulum effect capable of cracking or rupturing the container. A second problem is the tendency of the described cradle to stretch with continued use, thereby weakening the supporting capability of the same. Further, the necessity of a large number of hooks carried by the supporting cross bar which are mounted in holes in the bar, tends to permit the bar to bend in the medially disposed portions thereof under stress. Finally, in the case of composite products such as automotive wiring harnesses which must be held together during shipment, the harnesses have not provided adequate constraint upon the product prior to and after removal from the supporting cradle.